Theorem eximd ≪ | index | src | ≫

theorem eximd {x: nat} (G: wff) (a b: wff x):
  $ G -> a -> b $ >
  $ G -> E. x a -> E. x b $;

Step	Hyp	Ref	Expression
1		exim	A. x (a -> b) -> E. x a -> E. x b
2		hyp h	G -> a -> b
3	2	iald	G -> A. x (a -> b)
4	1, 3	syl	G -> E. x a -> E. x b

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp), axs_pred_calc (ax_gen, ax_4, ax_5)